spring5 webclient使用指南详解

之前写了一篇resttemplate使用实例，由于spring 5全面引入reactive，同时也有了resttemplate的reactive版webclient，本文就来对应展示下webclient的基本使用。

请求携带header

携带cookie

@test
  public void testwithcookie(){
    mono<string> resp = webclient.create()
        .method(httpmethod.get)
        .uri("http://baidu.com")
        .cookie("token","xxxx")
        .cookie("jsessionid","xxxx")
        .retrieve()
        .bodytomono(string.class);
    logger.info("result:{}",resp.block());
  }

携带basic auth

@test
  public void testwithbasicauth(){
    string basicauth = "basic "+ base64.getencoder().encodetostring("user:pwd".getbytes(standardcharsets.utf_8));
    logger.info(basicauth);
    mono<string> resp = webclient.create()
        .get()
        .uri("http://baidu.com")
        .header(httpheaders.authorization,basicauth)
        .retrieve()
        .bodytomono(string.class);
    logger.info("result:{}",resp.block());
  }

设置全局user-agent

@test
  public void testwithheaderfilter(){
    webclient webclient = webclient.builder()
        .defaultheader(httpheaders.user_agent, "mozilla/5.0 (macintosh; intel mac os x 10_12_6) applewebkit/537.36 (khtml, like gecko) chrome/63.0.3239.132 safari/537.36")
        .filter(exchangefilterfunctions
            .basicauthentication("user","password"))
        .filter((clientrequest, next) -> {
          logger.info("request: {} {}", clientrequest.method(), clientrequest.url());
          clientrequest.headers()
              .foreach((name, values) -> values.foreach(value -> logger.info("{}={}", name, value)));
          return next.exchange(clientrequest);
        })
        .build();
    mono<string> resp = webclient.get()
        .uri("https://baidu.com")
        .retrieve()
        .bodytomono(string.class);
    logger.info("result:{}",resp.block());
  }

get请求

使用placeholder传递参数

@test
  public void testurlplaceholder(){
    mono<string> resp = webclient.create()
        .get()
        //多个参数也可以直接放到map中,参数名与placeholder对应上即可
        .uri("http://www.baidu.com/s?wd={key}&other={another}","北京天气","test") //使用占位符
        .retrieve()
        .bodytomono(string.class);
    logger.info("result:{}",resp.block());

  }

使用uribuilder传递参数

@test
  public void testurlbiulder(){
    mono<string> resp = webclient.create()
        .get()
        .uri(uribuilder -> uribuilder
            .scheme("http")
            .host("www.baidu.com")
            .path("/s")
            .queryparam("wd", "北京天气")
            .queryparam("other", "test")
            .build())
        .retrieve()
        .bodytomono(string.class);
    logger.info("result:{}",resp.block());
  }

post表单

@test
  public void testformparam(){
    multivaluemap<string, string> formdata = new linkedmultivaluemap<>();
    formdata.add("name1","value1");
    formdata.add("name2","value2");
    mono<string> resp = webclient.create().post()
        .uri("http://www.w3school.com.cn/test/demo_form.asp")
        .contenttype(mediatype.application_form_urlencoded)
        .body(bodyinserters.fromformdata(formdata))
        .retrieve().bodytomono(string.class);
    logger.info("result:{}",resp.block());
  }

post json

使用bean来post

static class book {
    string name;
    string title;
    public string getname() {
      return name;
    }

    public void setname(string name) {
      this.name = name;
    }

    public string gettitle() {
      return title;
    }

    public void settitle(string title) {
      this.title = title;
    }
  }

  @test
  public void testpostjson(){
    book book = new book();
    book.setname("name");
    book.settitle("this is title");
    mono<string> resp = webclient.create().post()
        .uri("http://localhost:8080/demo/json")
        .contenttype(mediatype.application_json_utf8)
        .body(mono.just(book),book.class)
        .retrieve().bodytomono(string.class);
    logger.info("result:{}",resp.block());
  }

直接post raw json

@test
  public void testpostrawjson(){
    mono<string> resp = webclient.create().post()
        .uri("http://localhost:8080/demo/json")
        .contenttype(mediatype.application_json_utf8)
        .body(bodyinserters.fromobject("{\n" +
            " \"title\" : \"this is title\",\n" +
            " \"author\" : \"this is author\"\n" +
            "}"))
        .retrieve().bodytomono(string.class);
    logger.info("result:{}",resp.block());
  }

post二进制--上传文件

@test
  public void testuploadfile(){
    httpheaders headers = new httpheaders();
    headers.setcontenttype(mediatype.image_png);
    httpentity<classpathresource> entity = new httpentity<>(new classpathresource("parallel.png"), headers);
    multivaluemap<string, object> parts = new linkedmultivaluemap<>();
    parts.add("file", entity);
    mono<string> resp = webclient.create().post()
        .uri("http://localhost:8080/upload")
        .contenttype(mediatype.multipart_form_data)
        .body(bodyinserters.frommultipartdata(parts))
        .retrieve().bodytomono(string.class);
    logger.info("result:{}",resp.block());
  }

下载二进制

下载图片

@test
  public void testdownloadimage() throws ioexception {
    mono<resource> resp = webclient.create().get()
        .uri("http://www.toolip.gr/captcha?complexity=99&size=60&length=9")
        .accept(mediatype.image_png)
        .retrieve().bodytomono(resource.class);
    resource resource = resp.block();
    bufferedimage bufferedimage = imageio.read(resource.getinputstream());
    imageio.write(bufferedimage, "png", new file("captcha.png"));

  }

下载文件

@test
  public void testdownloadfile() throws ioexception {
    mono<clientresponse> resp = webclient.create().get()
        .uri("http://localhost:8080/file/download")
        .accept(mediatype.application_octet_stream)
        .exchange();
    clientresponse response = resp.block();
    string disposition = response.headers().ashttpheaders().getfirst(httpheaders.content_disposition);
    string filename = disposition.substring(disposition.indexof("=")+1);
    resource resource = response.bodytomono(resource.class).block();
    file out = new file(filename);
    fileutils.copyinputstreamtofile(resource.getinputstream(),out);
    logger.info(out.getabsolutepath());
  }

错误处理

@test
  public void testretrieve4xx(){
    webclient webclient = webclient.builder()
        .baseurl("https://api.github.com")
        .defaultheader(httpheaders.content_type, "application/vnd.github.v3+json")
        .defaultheader(httpheaders.user_agent, "spring 5 webclient")
        .build();
    webclient.responsespec responsespec = webclient.method(httpmethod.get)
        .uri("/user/repos?sort={sortfield}&direction={sortdirection}",
            "updated", "desc")
        .retrieve();
    mono<string> mono = responsespec
        .onstatus(e -> e.is4xxclienterror(),resp -> {
          logger.error("error:{},msg:{}",resp.statuscode().value(),resp.statuscode().getreasonphrase());
          return mono.error(new runtimeexception(resp.statuscode().value() + " : " + resp.statuscode().getreasonphrase()));
        })
        .bodytomono(string.class)
        .doonerror(webclientresponseexception.class, err -> {
          logger.info("error status:{},msg:{}",err.getrawstatuscode(),err.getresponsebodyasstring());
          throw new runtimeexception(err.getmessage());
        })
        .onerrorreturn("fallback");
    string result = mono.block();
    logger.info("result:{}",result);
  }

1. 可以使用onstatus根据status code进行异常适配
2. 可以使用doonerror异常适配
3. 可以使用onerrorreturn返回默认值

小结

webclient是新一代的async rest template，api也相对简洁，而且是reactive的，非常值得使用。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。